17 May

Hippocrates and his contemporaries knew remarkably little about human anatomy, the structure of the bones aside. They made no systematic distinction between arteries and veins. They could not distinguish nerves and tendons. They did not understand that muscles contract, and they very rarely used the word for ‘muscles’, normally speaking of ‘flesh’. This may seem surprising, as the sculptors of the fifth century bc portray heavily muscled bodies, and Greek athletes must have worked endlessly to develop their muscles. But in the language of the fifth century what was admirable about an athlete’s body was that it was (as modern translations have it) ‘articulated’ or ‘jointed’. A better translation might be to say that fifth-century Greeks admired ‘definition’, but they had no idea that muscles are required for definition. The contemporaries of Hippocrates not only lacked the idea of ‘muscles’, they also had no word for the stomach.

They thought the womb wandered around the female body, not only mounting into the chest, where it might cause suffocation, but even climbing as far as the head or descending into the big toe. They had no understanding of the role of the lungs in breathing, believing air went into the brain and belly. Crucially, their knowledge of the internal organs was based on what they could see when dealing with wounded patients and what they could learn from butchered animals. It is clear they never practised dissection on the human body: respect for the bodies of the dead, even of dead enemies, was fundamental to Greek culture. Aristotle was the first to practise dissection (and perhaps vivisec- tion) on animals. All societies cut up animals, and not just to eat them: many societies, including the ancient Greeks, foretold the future by inspecting the insides of animals. What was new in Aristotle was his conviction that every part of the body fulfilled a function: Aristotle invented the notion that the body is made of organs (the word ori- ginally means ‘tools’) that are designed to serve a purpose.

Aristotle believed the soul uses the body to serve its purposes, and it does so through the organs. Dissection for Aristotle was thus the study of function. He looked inside the bodies of animals to find out what each part did. And what he found was evidence of craftsmanship. The first detailed anatomical description is a description of the heart that is to be found in one of the pseudo-Hippocratic writings. The heart, it tells us, is ‘a piece of craftsmanship’, and this is the language that echoes through all later accounts of human anatomy.

The first to practise dissection on the human body was, it seems, Diocles, who was perhaps a pupil of Aristotle, and who wrote a now- lost book on anatomy. Aristotle’s teaching that ‘when the soul departs, what is left is no longer an animal, and that none of the parts remain what they were before, excepting in mere configuration’ per- haps helped overthrow what had been a fundamental taboo against cutting up human bodies. But the major revolution in anatomical thinking took place in Alexandria as a result of the work of Herophilus and Erasistratus, who were both born around 330 bc. According to later accounts they both practised vivisection: Alexan- dria was a despotism in which Greeks ruled over barbarians, and they may have been permitted to experiment on convicted criminals. Herophilus, in particular, established the anatomy of the brain and its relationship to the nerves, whose role in controlling movement he recognized. He also studied the reproductive organs, identifying the ovaries and the Fallopian tubes, and rejecting the view, which was still prevalent two thousand years later, that the womb moves about the body.

Herophilus’s teacher, Praxagoras, introduced a systematic distinction between arteries and veins, though he assumed (as did Erasistratus) that the arteries carried air, and gave to them the name also given to the trachea. It was Praxagoras who first identified the arterial pulse: Aristotle had thought that the heart and all the blood vessels pulsed together because he was unable to distinguish arteries from veins. Herophilus later explored the possibility of using the pulse for diagnostic purposes and devised a portable timepiece to measure its speed. As for Erasistratus, it is easy to mock his belief that in the uninjured body blood is confined to the venous system, while the arteries carry air; but he did accurately identify the heart as a pump with valves, even if he took it to be a form of bellows pumping air. What emerged from the work of Alexandrian anatomists was a major revolution in the understanding of the body and its relationship to the mind. In Homer, writing in the eighth century bc, there is no general term for body or for mind.

Moreover Homer has no way to say that someone made up their mind: he talks about the gods deciding what they should do. By the time we get to Aristotle in the fifth century bc soul and body are contrasted terms, and deliberation is a capacity of the soul. Moreover, the soul acts through the body, but some actions are deliberate, and some actions (e.g. breathing) take place without thought. After Herophilus there are two systems in the body. On the one hand the brain, the nerves, and the muscles (the word now becomes of crucial importance) control voluntary movement. On the other hand the heart, the arteries, and the veins represent systems over which the mind has no control, systems of involuntary action. This involved distinguishing terms that, for the followers of Hippocrates, had been near-equivalents. For the first Hippocratics the difference between pulses, palpitations, tremors, and spasms was merely one of scale: such tremblings could be seen in any part of the body. After Herophilus, the pulse (singular now instead of plural) occurred simultaneously and involuntarily in the heart and arteries; palpitations, tremors, and spasms were now afflictions of the nervous system, involuntary twitches of a system that should be under conscious control. The first Hippocratics had never taken the pulse of their patients, but now the pulse became a key source of information about the involuntary system, as opposed to the voluntary one. We now begin to get some sense of why the idea of self-control was so important to Galen.

To be human was to be in control of those bodily activities that were voluntary; to lose control, to strike and bite, was to allow the passions to seize control, and so to become an animal rather than a human being. There was, however, a fundamental ambiguity in this way of thinking. One could treat the voluntary and involuntary systems as two aspects of the human body, as Galen did, or one could see them as reflecting a fundamental distinction between the physical and the mental, between body and soul, between the passions and reason. If one went down this alternative route, dissection, which had started as a study of function, could now be said to have confirmed a fundamental claim of Socratic philosophy: that the mind was separate from the body, that mental functions and bodily functions were dif- ferent in nature. Thus the distinction between the veins and arteries on the one hand, and the nerves on the other, along with the recon- ceptualization of ‘flesh’ as ‘muscles’, was the physiological proof of the new philosophy. Previously not only had veins and arteries been lumped together as blood vessels but nerves and tiny arteries had not been distinguished. Now anatomy had shown that one could trace the contrasted ideas of voluntary and involuntary action through the finest details of the dissected body. How could one control those functions of the body over which one had no conscious control? It was medicine’s responsibility to answer this question. After Herophilus and Erasistratus not only vivisection but also dissection seem to have ceased. For several hundred years anatomical knowledge stood still because doctors no longer had access to bodies. One of Galen’s earliest works was an edition of the Anatomy of Marinus, and it seems that Marinus had turned to the dissection of apes in order to learn about human anatomy. Modern scholars believe that Galen himself never had an intact human body to dissect, and that his knowledge –– which was, as we shall see later, extensive –– derived from both dissection and vivisection of apes.

It is easy, when reading a work such as Galen’s On Anatomical Procedures, to be struck by the extent to which his knowledge of anatomy coincides with our own. But it is important always to remember that his understanding of biological processes is funda- mentally different from ours. Consistently, Greek doctors read the outside appearance of the body, and the substances excreted from it, as a sign of what is going on inside. Take hair. The Greeks were aware that the pores of the body transpire; when the vapour leaving the body is sooty, Galen held, a deposit could build up in the pores. When such a body blocks up the entire pore, it is then pushed out all at once by the pressure from the similar excretions behind it which have no path of escape. The substance, which has by now become wiry, is thus compelled to break through the skin . . . Black hair comes about when the vaporization is roasted by the strength of the heat in the body, so that the excretion becomes genuinely smoky; fair hair comes about when this heating effect is less. In that case the wedged-in substance is a sedimental product of yellow bile, not of the black variety. White hair is a product of phlegm. Red hair, whose colour is midway between fair and white, has an intermediate position in terms of its origin too: a sediment which is half-way between the phlegmatic and the bilious. Curly hair comes about either through the dryness of the mixture or because of the pore in which it is rooted . . . Thus every physiological process was to be understood in terms of the humours and the four basic qualities of hot and cold, dry and wet. Although Galen saw that a hair could be compared to a blade of grass with a root, he was only interested in it as part of a whole-body system, not as a distinct organ. This helps us to understand a puzzling feature of ancient medical thinking. In De Medicina (c. ad 40) Celsus says that ‘the Art of Medi- cine is divided into three parts: one being that which cures through diet, another through medicaments, and the third by the hand’. The idea that surgery is handwork is straightforward as the Latin word chirurgia derives from the Greek words for hand and work. But Celsus’ description of cure through diet includes not only regimen or the non-naturals, but also bloodletting and rocking (regarded as a form of gentle exercise; even the act of thinking was for Hippocratic doctors a form of exercise which warmed the soul), and the taking of purgatives and emetics: in other words all of what we would think of as internal medicine comes under the heading of dietary healing. Venesection and purging were considered, at the time, as being means of re- establishing the necessary balance that had been destroyed by unhealthy diet, and thus as extensions of dietary therapy.

When we turn to Celsus on medicaments we discover that this section of his work is not concerned at all with things like purgatives and emetics (which we might well think of as drugs) but only with substances applied topically to the body: oils, poultices, embrocations, liniments, and so forth. A hundred and thirty years later, Galen also assumes that a ‘drug’ is normally something applied to the exterior of the body. It works by entering through the pores; the finer the material the further it penetrates into the body. There, according to its nature, it warms or cools, dries or dampens the body. For Galen drugs that are ingested work in exactly the same way as those that are not ingested. But if they are ingested they function both as drugs and as food. Take let- tuce, which cools and is a soporific. Applied to the body its function is straightforward. Ingested, it initially functions as a drug; but when digested it functions as a food, and all foods have a heating quality and encourage wakefulness. Galen thus compares lettuce as a food to putting green wood on a fire –– initially it dampens the fire down, but in the end it burns brightly.

Historians of medicine happily report that Galen describes 473 ‘simples’ (uncompounded medicaments); that 1,000 had been listed in the De Materia Medica of Dioscorides (c. ad 60); that in the early eleventh century the Arabic scholar Ibn Sina or Avicenna lists 760 medicaments; and that towards the end of the twelfth century Ibn al-Bayatar lists over 1,400 medicaments. But this information is beside the point unless we remember that (with some exceptions, such as theriac, used both as an antidote to vipers’ bites and as a general tonic, which was held to work by its ‘specific form’) medicaments were understood simply to heat and cool, dry and dampen, and were therefore almost infinitely substitutable one for another. Language consistently tricks us into thinking that there are continuities where none exist. Our word ‘medicine’ when it is used to mean a drug comes from the title of Dioscorides’s De Materia Medica; our word pharmacy comes from the ancient Greek, where, as in Latin and English, the word for both the science of medicine and for a medic- ament is the same; the word drug itself is of Arab origin.

Because we owe our language to the Greeks, the Romans, and the Arabs it is easy to think that our words mean the same as theirs did; but medicine is no longer what it was for Dioscorides. Hippocratic doctors did not treat diseases; in their view diseases were themselves symptoms of an underlying imbalance of the humours; it was therefore the patient, not the disease, that had to be treated. To work through the list of Hippocratic medicaments, as modern scholars do, looking for ones that we would take to be effect- ive –– not lettuce, for sure –– is to miss the point that drugs were rarely ‘specifics’, directed at specific diseases (the case for such drugs was first argued by Paracelsus in the sixteenth century, using the example of mercury as a treatment for syphilis), and that our belief, for example, that bathing a wound in a liquid containing alcohol might have an anti-bacterial effect would have been incomprehensible in a world where there was no concept of infection. One of Harvey’s claims for his theory of the circulation of the blood was that it at last made it possible to understand how drugs could quickly take effect throughout the body; without such a theory all drugs had to be understood as being local in their impact. Prior to Harvey, materia medica was first and foremost about ointments, not drugs, even when they were ingested into the body.

And what these ointments could be understood to do was constrained by the humoral theory that governed their use. Between Polybus and Galen that theory had been developed and refined. For the next fourteen or fifteen hundred years doctors were more concerned to preserve and transmit this intel- lectual inheritance than to question or improve it.

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